Your Food Scraps Could Help Fight Climate Change

The fight against climate change is no longer just about cutting emissions; it’s also about pulling carbon dioxide out of the sky. To keep global warming below 1.5°C, the Intergovernmental Panel on Climate Change (IPCC) warns that humanity must remove and store hundreds of billions of tonnes of CO₂.

For years, companies like Climeworks have pioneered direct air capture (DAC), building machines that filter CO₂ from the atmosphere. But the technology remains costly and energy‑intensive. Now, researchers at ETH Zurich have unveiled a strikingly simple alternative: porous protein beads made from food industry waste.

Led by materials scientist Raffaele Mezzenga, the team turned leftover whey from dairies and by‑products from tofu production into long protein chains called amyloid fibrils. These fibrils were loaded with potassium hydroxide and shaped into beads about half to one centimeter wide.

“The resulting material is like a sponge that can absorb large quantities of CO₂ via the potassium hydroxide,” Mezzenga explains.

When exposed to air, the beads capture CO₂ by converting it into hydrogen carbonate. In lab tests, one gram of beads absorbed 97 milligrams of CO₂, 10 to 50 percent more than conventional DAC materials.

“In our tests with ambient air, we were able to extract 97 milligrams of CO₂ with one gram of material,” says Zhou Dong, lead author of the study. “This is a very high rate.”

Traditional DAC systems require heat and negative pressure to release CO₂, consuming vast amounts of energy. The ETH Zurich method instead uses a gentle spray of acid and base at room temperature, breaking chemical bonds and freeing the CO₂ for storage or reuse.

“The synthetic materials that are used to capture CO₂ today decompose quickly. By contrast, our protein beads remain stable for a long time,” Dong explains.

The team tested 30 adsorption‑release cycles without a loss of efficiency. Even after thousands of cycles, when the beads eventually degrade, they can be repurposed as fertilizer or biofuel. Made entirely of organic material, the beads are biodegradable, closing the loop in a circular economy.

“The materials we use for this process are non‑toxic and food‑grade,” Mezzenga points out. A life cycle analysis showed that their method generates less environmental pollution than other DAC approaches.

The researchers demonstrated the system with a few grams of beads, binding around 50 grams of CO₂. Scaling up remains the next challenge. Dong will lead further studies to test whether the high absorption capacity holds at larger volumes.

Mezzenga is optimistic. Having worked with amyloid fibrils for nearly 20 years, he has already used them to create biodegradable plastics and water purification systems. “We’re confident that the technology is scalable,” he says.

Although the team has not yet calculated the exact cost per tonne of CO₂ captured, Mezzenga expects it to be significantly lower than conventional DAC.

“Our technology is cheaper and more sustainable because it requires little energy and is based on a widely available waste product,” he says. “That could be a game changer for the future of removing CO₂ from the air.”

If successful, this approach could transform DAC from a niche technology into a widely deployable solution. Imagine dairies and tofu factories turning their waste streams into carbon‑capture beads, or communities using locally produced materials to build affordable CO₂ filters.

By turning discarded proteins into climate tools, the ETH Zurich team has shown that solutions to global warming may lie not in futuristic machines, but in everyday waste.

In the fight against climate change, the humble protein bead could become a powerful ally, absorbing the invisible gas that threatens our planet with simplicity, sustainability, and surprising elegance.